I'm Not Sure Why This Is Happening

Ok so this has been happening to me for a few days now and I'm not sure why. Nothing has been happening anywhere else on my computer so I think it has something to do with my League itself. I tried a few things to fix it like lowering my settings bc it also seemed like my fps was dropping but it wasn't. If anyone knows why this is happening or what i could do to fix it, please tell me.